This invention is generally related to test equipment, and more particularly to test equipment for wireless network emulation. Cellular networks and Wireless Local Area Networks (“WLANs”) enable communications between mobile wireless devices such as user terminals (UEs), which can include mobile phones and portable computers, and fixed location wireless devices such as access points and base stations. It is standard practice to test the performance of such devices under various network conditions. Testing wireless devices in an open environment is notoriously difficult because wireless communications can be affected by ambient sources of interference. However, it is now relatively common to use system level network emulators to perform wireless device testing in a controlled environment. One type of emulator includes a separate container for each wireless device to shield against external electromagnetic interference (EMI). Communications are converted from wireless radio frequency (RF) to wired signals, and the containers are placed in communication via wired connections. A channel emulator connected between the containers subjects the communications to simulated physical environmental effects.
Various types of tests can be performed with a channel emulator. For example, the tests can be designed to create either hypothetical conditions or recreate realistic conditions. One type of realistic test is system level network emulation. In a system level emulation the system level network conditions experienced by a wireless network are recorded and subsequently recreated in the lab using the channel emulator. More particularly, the conditions are recorded in log files saved by different components of the telecommunication network. These logs are synchronized, combined and processed to create a playback file which is used to recreate the real network behavior. The recreated conditions emulate the telecommunication network in terms of number of available sectors and pilot signals, power of pilot signals, received signal power levels, and signal-to-noise-plus-interference ratio (SNIR). Such an emulation can be used for evaluation of access events such as random access of the network, connection events such as call drops, mobility events such as hand-off, average sector throughput, average delay, average network throughput, and the performance of different traffic types such as best effort (BE), expedited forwarding (EF), and assured forwarding (AF).